rv7charlie
Well Known Member
My statement:
Originally Posted by rv7charlie View Post
If you think about it, a modern battery is extremely reliable. If maintained properly, it's probably the most 'reliable' component in the plane. So why are there two?
1st, my mistake for not specifying 'modern *sealed lead acid* battery'. The various lithium chemistries are still a big wild card to introduce, especially when they interact with another other new variable.
Now that that is out of the way, aren't you making my point? If redundancy is highly recommended, shouldn't all single points of failure that negate the redundancy be eliminated, as well? If you'd quoted the rest of that post, you'd have seen:
Something that comes up all the time on the Aeroelectric List is not designing for reliability (which should be a given), but for redundancy. If you think about it, a modern battery is extremely reliable. If maintained properly, it's probably the most 'reliable' component in the plane. So why are there two?
That last question was rhetorical; Of course you want redundant power. But if the non-redundant delivery is the failure point, then it's just dead weight. (Pardon the pun.)
Last, I'm more comfortable with redundant generating systems (which will weigh less) with redundant paths , than with redundant batteries, which still have (highly variable) endurance limits even if they don't actually fail. Yes, you can do both, but should we add an extra set of wings, as well? (Rhetorical question.)
Charlie
Originally Posted by rv7charlie View Post
If you think about it, a modern battery is extremely reliable. If maintained properly, it's probably the most 'reliable' component in the plane. So why are there two?
Boy, the interwebs are a tough place to communicate.Batteries have been known to take an unexpected dump, especially some lithium ones. With a battery dependent ignition system, you lose a single battery, the engine stops. That's a good reason for a second one in my view. I have personal experience in this regard...
We never recommend anyone running two EIs in an aircraft to use a single battery.
1st, my mistake for not specifying 'modern *sealed lead acid* battery'. The various lithium chemistries are still a big wild card to introduce, especially when they interact with another other new variable.
Now that that is out of the way, aren't you making my point? If redundancy is highly recommended, shouldn't all single points of failure that negate the redundancy be eliminated, as well? If you'd quoted the rest of that post, you'd have seen:
Something that comes up all the time on the Aeroelectric List is not designing for reliability (which should be a given), but for redundancy. If you think about it, a modern battery is extremely reliable. If maintained properly, it's probably the most 'reliable' component in the plane. So why are there two?
That last question was rhetorical; Of course you want redundant power. But if the non-redundant delivery is the failure point, then it's just dead weight. (Pardon the pun.)
Last, I'm more comfortable with redundant generating systems (which will weigh less) with redundant paths , than with redundant batteries, which still have (highly variable) endurance limits even if they don't actually fail. Yes, you can do both, but should we add an extra set of wings, as well? (Rhetorical question.)
Charlie